A copper rod and a steel rod are heated. At 0°C, the copper rod has a length LC and the steel one has a length LS . When the rods are being heated or cooled, a difference of 5.00 cm is maintained between their lengths. Determine the values of LC . αCu = 5 × 10–5/°C, αs = 2 × 10–5/°C.
(A) 3.33 cm
(B) 5 cm
(C) 8.33 cm
(D) 15 cm
Correct Answer is: (A) 3.33 cm
LC αCu = LS · αS ⇒ 5LC = 2LS ....... (i)
LS – LC = 5 cm ...... (ii)
2.5 LC – LC = 5
1.5 LC = 5
LC = 5 x 2/3 = 10/3 = 3.33 cm
